Field of the Disclosure
The present disclosure relates to a display device, and more particularly, to a display device with an integrated touch screen.
Discussion of the Related Art
A touch screen is an input device installed in an image display device implemented using technology such as a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an electroluminescence device (EL), an eletrophoretic display (EPD), etc., to allow a user to input predetermined information by pressing (or touching) a touch sensor in the touch screen while viewing the image display device.
Touch screens are classified into three types depending on a structure of a touch screen installed in a display device: an add-on type, an on-cell type and an in-cell type. An add-on type touch screen is manufactured separately from a display device and is attached on an upper substrate of the display device. An on-cell type touch screen comprises elements directly formed on an upper substrate of a display device. An in-cell type touch screen is built in a display device such that the display device has a thin thickness and improved durability.
A display device with an add-on type touch screen has disadvantages of a thick thickness and low visibility from low brightness. Although it has a thinner thickness than the display device with an add-on type touch screen, a display device with an on-cell type touch screen has disadvantages of increased total thickness, manufacturing processes and manufacturing costs because of driving electrodes, sensing electrodes, and an insulating there between for the touch screen.
On the other hand, a display device with an in-cell type touch screen, which may be referred to as a display device with an integrated touch screen, is able to improve durability and have a thin thickness, thereby solving the problems of the display device with the add-on type touch screen and the display device with the on-cell type touch screen. The display device with an in-cell type touch screen may again be divided into two categories: an optical type and a capacitive type. The capacitive type may be categorized into self capacitance type and mutual capacitive type.
A display device with a mutual capacitance in-cell type touch screen includes a common electrode divided into driving electrodes and sensing electrodes such that mutual capacitance is generated between the driving electrodes and the sensing electrodes and measures a change in the mutual capacitance due to a touch of a user, thereby detecting the touch. A display device with a self capacitance in-cell type touch screen includes a common electrode divided into a plurality of parts such that the plurality of parts are used as touch electrodes and capacitance is generated between the touch electrodes and an input of a user, and a change in the capacitance due to a touch of the user is measured, thereby detecting the touch.
In the display device with a self capacitance in-cell type touch screen according to the related art, each touch electrode formed by dividing the common electrode and includes blocks generates capacitance with the touch electrodes and the lines adjacent thereto, and the initial capacitance varies depending on the number of neighboring touch electrodes, an overlapping area of the touch electrode with the lines, and so on.
Particularly, the initial capacitance increases as the touch electrode increase, the number of neighboring touch electrodes increases or the overlapping area of the touch electrode with the lines increases. In this case, the change in the capacitance due to the touch of the user is decreased, which in turn decreases the touch sensitivity.
In addition, in the self capacitance in-cell type touch screen, the number of neighboring touch electrodes and the overlapping between the touch electrode and the lines are larger than those of the mutual capacitance in-cell type touch screen. The initial capacitance in the self capacitance in-cell type touch screen is larger than those of the mutual capacitance in-cell type touch screen.